//An official at China’s agriculture ministry said recent outbreaks of African swine fever (ASF) originated outside China, state radio reported on Wednesday

//China has confirmed four cases of African swine fever in four provinces in less than a month and has culled more than 25,000 pigs, highlighting the challenge of containing the highly contagious disease

//Wang Gongmin, deputy head of the husbandry and veterinary bureau under the Ministry of Agriculture and Rural Affairs, said China had tested more than 20,000 other samples for ASF and all were found to be negative, according to the report

//He did not say which country may have been the original source of the disease